Moisture control in an electromechanical device



2 Shets-Sheet 1 FIG. 2

INVENTOR LGBOSTW/CK av ATTOP EV Filed Sept. 15, 1942 L G BOSTWICK MOISTURE CONTROL IN AN ELECTROMECHANICAL DEVICE y 1946- L. G. BOSTWICK 8 MOISTURE CONTROL IN AN ELEQTROMECHANICAL DEVICE Filed Sept. 15, 1942 I Z -SheetS-Sheet 2 68 G 4 IN [/5 N 7' OR By LG; BOSTW/CK ATTOR EV Patented July 30, 1946 airl nes MOISTURE CONTROL IN AN 'EIIEGTRG.- MECHANICAL DEVICE L .G- h s iek Gha J assi i e to Bell Telephon Labo at r e incor ora ed, Ne York, N. Y., a corporation of New York App at n .Ser em er 15, 2,-.Seria1 fio 51. 421

1 Claim. 1

This invention relates to electromechanical de.- vices and, more particularly, to submarine sig: naling devices.

An object of the invention is to improve the structure of such devices and, more particularly, of submarine signal wave projectors or radiators.

Submarine signal devices are known in which the hydrostatic pressure on the moving system or diaphragm of the device is compensated or balanced in whole or in part, for example, by ga see ous pressure on the non-exposed side of the ,diaphragm. The means enablingsuch pressure com,- pensation or balancing may involve a OH Pre sible member, such as a bellows or a collapsible container or bag, adapted to be exp sed in whole or in part to the liquid medium, that is, to the water, the interior of the container being coupled to or connected with the space or chamber adjacent the non-exposed side of t e dia hra m. If the material of the compressible member is to any extent pervious to water, there will be a tend-v e c r t water o di u e e otherwise pen trate therethrough and into the interior of the si a e with he atte dant pes ihilii ei corrosive action tending to shorten the useful iife of the device, or requiring more frequent removal of the device from the water and its dismantling for inspection. Not only may the liquid medium find entrance into the device in this manner, but

the presumably water-tight joints of the structure may in time permit the entrance of some water. In certain devices, also, the pressure balancing action has been obtained. by using a flexible or distendable wall portion of a material, such as rubber, through which the liquid medium may in time, even though at a slow rate, find in gress to the interior of the device.

A feature of the invention comprises providing a desiccant or drying agent in signal devices used in a liquid medium.

Another feature comprises employing as a desiccant in such devices a material experiencing substantially no chemical or physical change in the presence of water or water vapor.

A further feature comprises the employment in such devices of a desiccant of the adsorption type,

Still another feature comprises utilizing in such devices a desiccant comprising a finely divided, activated oxide capable of being reactivated and reused repeatedly.

In accordance with this invention, an electromechanical transducer comprising a hollow enclosure for a transducer unit, and which enclosure includes a wall portion through which liquid or liquid vapor, specifically, water or Water v ma ,cl f een epor the wise have ingress, is arranged to enclose a desiccant or drying agent to deprive or exhaust the interior .of h ehelesure o i u d or l quid a o th may find entrance thereinto The desiccant may be en t x ie c s ti l y no chemica r physical change in the presence of th liquidor l d va o a may b i ne y ivi d, a tiv ed oxide that may be reactivated and reused re- Deatedly, Such a drying agent may have an ad-, erption haract risti and spec fica ma he silica ge A more complete understanding of this invenio wi l b eri ed rom the deta l d d cr ti hat fell ws ead ith re e ence t the d pan ing drawin wherein Fig. 1 is an elevational view of a submarine signa seure gpr i e r rad t r i hic the inve tiei m b emb d;

2 is an elevational View of a fragment of the device of Fig. ;l, partly broken away and partly in section to show structural details thereof;

li 'ig. 3 is a cross-sectional view of the signaling device included in the projector of Fig. 1, along the line $3 of Fig. 1; and I Fig. 4 illustrates a' container or enclosure for a desiccant that has been found satisfactory'in practicing this invention.

The present invention is disclosed with specific reference to a submarine signal projector of the general type disclosed in the pending application of L. G. Bostwiek and J. H. King, Serial No, 445,- 97 i, filed Jun 5, 1942, for Electromechanical device, and, more particularly, to a projector of the type described in that application with particular reference to Figs. 1 to 6, inclusive, of the drawings thereof.

The sig-nal wave source,- projector or radiator IE] illustrated by Fig. 1 of the attached drawings, comprises an energy radiating device or portion H, a hydrostatic pressure compensating or balancing device or portion l2, and rigid means l3 interconnecting the devices ll, [2, whereby the projector comprises a unitary structure that may be supported under water at the end of suitable wires or cables I4 that may be secured to the projections or ears l5 on the device l2.

Fig. 2 of the attached drawings is an enlarged detail of the device [2, and'a portion of the rigid interconnecting means l3, partly broken away and partly in section better to illustrate the structure involved. The arrangement is substantially the same as that of the Bostwick-King application except that in one respect the conductors for connecting the device ll with other electrical equipment, are provided through a cable 90'. The cable 96' is brought into the projector through a water-tight gland or stuiiing box 98A, which may contain a splice (not shown) a portion of which gland is threaded into the cover member or plate 15'. The cover member is so shaped adjacent the container 10 that a plurality of slitspr slots 16A are provided for the ingress of the liquid medium into the interior of the container 10. The concentric inner pipe 66, and outer pipe 68, the rigid casing or container it, the valve coupler 15, the valve 79, the metallic tubing 80, the union 8 I, the pet-cock E4 and the compressible member, container or bag It may be similar in construction and perform the like function to the corresponding components in the aforementioned BOStWiCK- King application. The compressible member 18 is of an elastic material, such as rubber, the interior 82 of which communicates through the valve 19, tubing 80, the coupler l and the pipe 55 with the chambers ii, &2 and 62 of the device i I. The shape of th member 18 is shown such as it might assume when the projector H! is submerged under water and the latter has entered through the slits 16A to fill the container space not occupied by the member 78, and to fill the space between the pipes 56, 68. The device H, as shown in Fig. 3 of the drawings attached hereto, is seen to be substantiall the same as the device illustrated in cross section in Fi 3 of the aforenoted BostWick-King application, except that it embodies the component 5 of which more description hereinafter.

It has been ascertained that water or water Vapor may find entrance to the interior of the projector, particularly by difiusion through the material of the compressible member 78 into the chamber 32 thereof, and through the tubing 80 and pipe 56 into the interior of the device H. Such moisture may cause corrosion of the device, particularly at th terminals, the coil leads and l e diaphragm thereof. Although a certain amount of such corrosion might be sustained by the device without affecting its operativeness, in the absence of any special provision limiting such effect, frequent dismantling and inspection would be necessary, attendant with necessary removal of the projector from its under-water location and substantially no chemical or physical change in the presence of water. It may comprise a finely divided, activated oxide capable of being reactivated and reused repeatedly. Such a material is silica gel. This material may be included in the component designated 5, and shown in Figs. 3 and 4 of the attached drawings. The container, enclosure or carrier I for the desiccant 2 may comprise a strip of woven material or fabric, such as muslin, having a multiplicity of apertures or interstices for the ready penetration of liquid or liquid vapor, a portion of the material being folded back on itself and sewed at its edges 3, 4 as well as at a plurality of intermediate portions 6 to define a plurality of pockets 7 to be filled with the desiccant at least to the level indicated by the dotted line. The flap portion 8 is adapted to be folded over the pockets so that it efiectively closes the otherwise open ends thereof and, when the component 5 is fitted around the annular magnet structure 25, is adjacent the latter. The desiccant component 5 may be fastened to the magnet structure by a tape or brush 9 secured in or to the woven material, and tied together at its end portions 9.

Other desiccants, of course, may be used, but silica gel has been found particularly satisfactory with respect to the particular environment involved. Although the invention has been disclosed with reference to a specific embodiment thereof, it will be understood that this is believed at this time to be the best mode of practicing the invention, and is not intended to constitute a limitation upon the scope of the invention.

What is claimed is:

An underwater wave translating device comprising a hollow container, a wave translating unit including a diaphragm mounted in the Wall of said container so that the outer side of said diaphragm engages the water, a submersibl hollow chamber having an elastic wall pervious to water, hollow means having a wall impervious to water for interconnecting the interiors of said container and said chamber, said container, hollow means and chamber being filled with an inert gas, said chamber changing its volume in response to variations of hydrostatic pressure and thereby varying the gas pressure on the inner side of said diaphragm substantially to compensate for the variations of hydrostatic pressure on the outer side of said diaphragm, and desiccating means positioned interiorly of said container for adsorbing water vapor passing thereinto as a consequence of diffusion through said chamber wall.

LEE G. BOSTW'ICK. 

